val 0.3.6

fn map(l, f) {
  i = 0

  result = []

  while (i < len(l)) {
    result = append(result, f(l[i]))
    i = i + 1
  }

  return result
}

fn double(x) {
  return x * 2
}

fn even(x) {
  return x % 2 == 0
}

fn filter(l, f) {
  i = 0

  result = []

  while (i < len(l)) {
    if (f(l[i])) {
      result = append(result, l[i])
    }

    i = i + 1
  }

  return result
}

fn reduce(l, f, initial) {
  i = 0

  result = initial

  while (i < len(l)) {
    result = f(result, l[i])
    i = i + 1
  }

  return result
}

fn sum(a, b) {
  return a + b
}

fn max(a, b) {
  if (a > b) {
    return a
  } else {
    return b
  }
}

l = [1, 2, 3, 4, 5]

println(map(l, double))
println(filter(l, even))
println(reduce(l, sum, 0))
println(reduce(l, max, l[0]))